1. Field of the Invention
The present invention is directed toward lubricating oil compositions containing Bis-Mannich base inhibitors, and to a process for their preparation. The Bis-Mannich base inhibitors employed in the lubricating oil compositions of this invention are represented by the Formula I: ##STR1## wherein R.sub.1 is independently alkylene of from 1 to 4 carbon atoms; R.sub.2 is alkylene of from 2 to 6 carbon atoms; R.sub.3 and R.sub.4 are independently hydrocarbyl of from 1 to 30 carbon atoms with the proviso that the sum of all R.sub.3 and R.sub.4 hydrocarbyl carbon atoms is sufficient to render the compounds of Formula I oil soluble; R.sub.5 is independently selected from the group consisting of hydrogen, alkyl of from 1 to 6 carbon atoms, phenyl and phenyl substituted with 1 to 2 substituents selected from hydroxy and alkyl of from 1 to 6 carbon atoms; and salts thereof.
2. Prior Art
Oils suitable for lubricating internal combustion engines are generally either mineral oils or synthetic oils of lubricating viscosity. In either case, during engine operation, these oils are subject to degradation resulting in harmful deposits and varnish formation in the engine. In order to prevent deposit and varnish formation, the present invention is directed to lubricating oil compositions containing deposit inhibitors. In particular, the present invention is directed toward lubricating oil compositions containing a new class of deposit inhibitors which are Bis-Mannich base inhibitors represented by Formula, I above.
U.S. Pat. No. 2,967,196 discloses certain ethylene diamine diacetic acids containing phenolic groups useful for chelating polyvalent metal ions in neutral and alkaline aqueous solutions.
U.S. Pat. Nos. 3,632,637 and 3,758,540 disclose iron chelates of N-(2-hydroxybenzyl)-substituted amino polycarboxylic acids. These compounds are disclosed as a source of iron for plants growing in alkaline soils.
U.S. Pat. Nos. 2,624,757 and 2,794,818 disclose halo substituted aralkyl alkylene diamine diacetic acids and salts thereof useful as bactericidal and fungicidal agents.
However, none of these references discloses lubricating oil compositions containing the Bis-Mannich bases of this invention nor does any of these references suggest that these Bis-Mannich bases would possess deposit inhibiting properties.